1. Field of the Invention
This invention relates to a method and apparatus for generating power. This invention relates to a method and apparatus for generating power using gas turbines. This invention relates to a method and apparatus for generating power using gas turbines in which the fuel-to-power efficiency compared to conventional gas turbine power generating systems is improved and NOx emissions are reduced. This invention further relates to a method and apparatus for generating power using air-staged reheat gas turbines. In addition to providing significant improvements in both system efficiency and NOx emissions compared to conventional systems, this invention reduces the amount of thermal energy in the turbine exhaust of gas turbines employed in the system.
2. Description of Related Art
Gas turbines are one of the major sources for power generation in use today. However, the best efficiency achieved to date using gas turbines is only about 38%. One significant drawback of gas turbines is that a significant portion of fuel energy input to the gas turbines, approximately 62-75%, is lost in the turbine exhaust. This exhaust energy is in the form of thermal energy only, which makes it difficult to use for effective power generation. Staged reheat gas turbines have the capability to improve both efficiency and NOx emissions. In some gas turbines, fuel staging has been employed. Fuel staging improves system efficiency but has limited application due to combustion instability problems, particularly in the first stage, high NOx emissions, and a large portion of thermal energy, about 55-65%, in the turbine exhaust. It will, therefore, be apparent that there is a need for a power generation system employing gas turbines which provides significant improvements in both system efficiency and NOx emissions, as well as reduces the amount of thermal energy in the turbine exhaust.